The present invention relates to a filtration arrangement of a vacuum cleaner, and more particularly to such a vacuum cleaner having a more direct air path to the suction motor and further, wherein the filter member is positioned at the top of the dustcup.
Many vacuum cleaners sold today are of the xe2x80x9cbaglessxe2x80x9d variety as opposed to the more traditional bagged vacuum cleaner that requires the consumer to change the filter bag periodically. With a bagless vacuum cleaner there is typically provided a transparent non-permeable reservoir referred to herein as a xe2x80x9cdustcup.xe2x80x9d The dustcup can be easily removed and emptied into a trash receptacle. Additionally, the dustcup is usually made of a transparent or translucent plastic material thus giving the consumer the ability to view the cleaning action and to view when the dustcup is in need of emptying. In the operation of a bagless vacuum cleaner, working air created by the suction source enters a nozzle and carries dust and debris into a cyclone so that it can be deposited into the dustcup. A filter or filters in the system may be provided to assist in the final separation of fine dust that may not have been completely removed by the cyclonic action. From such a filter assembly, clean air is then ultimately expelled to atmosphere.
An example of a bagless vacuum cleaner of this type can be found in U.S. Pat. No. 6,070,291 issued to Bair et al. on Jun. 6, 2000. In this patent, a vacuum cleaner dirt container has an inlet at the top and a suction motor located directly beneath the container. A cylindrical filter element extends centrally within the container from top to bottom. Air enters the top inlet of the container, circles the filter element, enters the filter element and then travels through an internal passage of the filter to the bottom of the container and into the suction motor. There are several disadvantages with this approach. First, by disposing the filter element so that it extends from the top to the bottom of the container, the bottom portion of the filter can clog since it is in direct contact with the larger particles of dust and debris deposited during the cyclonic cleaning operation. Also, the space occupied by the filter element diminishes the fill volume of the container and further, results in a strained, turbulent air path within the dirt container. Accordingly, it would be advantageous to provide a bagless vacuum cleaner that included a filter arrangement that resides away from the bottom of the dirt container thus allowing for the maximum fill volume within the container and further, achieved such a filter function in a way to maintain a non-turbulent air path within such container.
Another example of a similar bagless vacuum cleaner can be found in U.S. Pat. No. 6,192,550 issued to Hamada et al. on Feb. 27, 2001. In this patent, it can be seen that a filter portion is mounted at a higher position within the dirt container. Although the Hamada vacuum cleaner contains an elevated filter portion, such elevated filter portion is only one part of a complex filter arrangement that includes a pre-filter that completely surrounds the main filter. Such a configuration has the effect of reducing the fill volume within the dirt container and of contributing to a strained turbulent air path within the dirt container. Additionally, such a filter configuration, because of its complexity, will require the operator to conduct a multi-step operation each and every time it is necessary to empty the dirt container and perform a cleaning operation on the filter configuration. Of course, it would be more advantageous if such a bagless vacuum cleaner provided a filter configuration that would be easier for a consumer to operate and would not suffer from a reduced fill volume and strained, turbulent air path that results from the configuration of the Hamada patent.
In accordance with the principles of the present invention, there is provided a filtration arrangement of a vacuum cleaner comprising a floor engaging base unit, a body portion pivotally mounted on said base unit, and a suction motor/fan assembly mounted in one of the base unit and body portion. A dirt receptacle or dustcup is mounted on the body portion, and a cover member is sealingly mounted on the dirt receptacle. A first air path extends from the base unit to the cover member. The cover member comprises a curved inclined channel for imparting rotational motion to airflow entering the cover member from the first air path. An air tube is disposed centrally within the dirt receptacle and extends from a bottom end of the dirt receptacle toward a top end of the dirt receptacle. A removable filter mounted over a top portion of the air tube. The removable filter comprises an inner diameter opening that fits over the air tube in a manner to establish a second air path from the dirt receptacle to outside atmosphere through the suction motor/fan assembly.
According to another aspect of the invention, the vacuum cleaner further comprises a HEPA filter disposed between the suction motor/fan assembly and atmosphere.